Underground pipelines are commonly used throughout the world to transport various materials from one location to another. conventionally, the pipes which eventually form the pipeline system are provided with a protective coating at some point prior to burial. This protective coating deteriorates over time thereby necessitating the removal of the deteriorated coating and application of a new protective coating to prevent the pipeline from being damaged.
Different arrangements for cleaning the exterior surface of a pipe have been previously proposed and implemented. However, those previously employed systems have been fraught with design flaws which sacrifice economies of time, labor and money. Presently available pipe cleaners or pipe coating removers include assemblies which use spring loaded knife blades connected to a rotating ring driven concentrically around the pipe. This system is used to remove coal-tar type coatings. This system is disadvantageous in that, once the coal-tar type coatings become pliable, they tend to build up on the knife blades rendering the blades incapable of effectively removing the deteriorated coating. This results in significant delays while the knife blades are cleaned. Still other systems have required the pipeline to be removed from the burial ditch prior to refabrication of the protective coating.
The present invention is directed to a self-propelled carriage assembly for removing deteriorated coatings on pipelines. The carriage assembly employs a pair of endless flexible members wrapped around the outer surface of the pipe. The endless flexible members travel about the pipe at a high velocity, and preferably in opposite directions and, therefore, the centrifugal force generated frees the deteriorated coating from the chains. This process of freeing the coating material from the chains is further enhanced by the flexing of the flexible members as they travel over the corresponding drive pulleys or sprockets. Thus, the present invention does not encounter significant delays due to build-up on the cleaning tool. This advantage as well as others are obtained by the present invention as will be readily apparent from a review of this specification and accompanying drawings.